Pump piston



J. w. KELLY 2,362,139

PUMP PIsToN Filed sept. 21, 1942 Nov. 7, 1944.

:'1. l A T /3 @I l Pf3/66 F2@ V Patented lNov. 7, 1944 PUMP rls'roN 1 John William Kelly,I La Canada, Calih, assignor to Adel Precision Products Corp., a corporation of California Application September 21, 1942, Serial No. 459,199

10 Claims.

'I'his invention relates to hand pumps for emergency use in the hydraulic systems of aircraft and the like and more particularly has to do with the construction of the pistons for such pumps. i,

It has been the practice in this art to provide the piston rod and piston as separate units threadely coupled to one another and constructed in such manner as to necessitate the removal of the piston from the rod to assemble, disassemble and replace the piston-carried valve parts and seals which provide for the double action pumping operation usually employed in these pumps. This construction is also objectionable in that the threaded connection of the piston and rod vmakes it diiiicult to achieve and maintain the proper alignment of the piston and rod.

It is the primary object of the present invention to provide a new and eiicient piston assembly for pumps of the character described whichconsists of fewer separate parts, may be liable and emcient manner over longerV periods of use.

A further object of this invention is to provide a piston assembly of the character described having a novel removable valve seat held i'n place by a removable fastening and subject to ready and easy replacement, these parts and their relation to one another and the piston simplifying the construction of the piston and the machining operations and increasing the life of thev assembly as well as reducing the servicing costs thereof. l I

'With the foregoing objects in view, together 5 with such other objects and advantages as may subsequently appear, the invvy't'iomresides in vthe parts and in the combinati n, construction and arrangement of parts hereinafter describedl and claimed, and, illustrated by way of example in f the accompanying drawing, in which:

Fig. 1 is -a fragmentary sectional, part elevational view of the hand pump embodying the present invention;

Fig. 2 is a sectional view taken on the line 2--2 vof Fig. l with the barrel omitted;

Fig. 3 is a sectional view taken on the line 3-3 of Fig. 1 with ythe barrel omitted;

Fig. 4 is anexploded view of the piston assembly embodying the present invention;

Fig. 5 is a reduced fragmentary side elevation of a complete pump'embodying the present invention. The accompanying drawing shows one embodiment of my improved double-acting piston assembly generally designated I and which forms a part of an emergency hand pump. This pump also includes a body `2, a pump barrel or cylinder 3 as an integral part of the body, lugs 4 for securing the body to a support, a lever supporting bracket 5 at, an end of the body, a lever 6 pivoted on the bracket, a link 'I operatively connecting the lever with the piston assembly, a valved intake port 8 through which iluid enters the barrel, and an outlet port 9 through which fluid is pumped from Ithe barrel per stroke of the piston.

In accordance with the present invention the piston assembly I comprises a piston vrod III and a piston II which latter is formed as an enlarged integral end portion of the rod while l the other end of the rod is provided with an. ear I2 pivoted at I3 to the link 'I whereby the piston may be reciprocated in the pump barrel 3 through a suitable packing gland assembly I4.

A bore I5 is extended axially through the piston from the outer endV thereof and well into the rod, said bore being in communication with the interiorof the pump barrel through radial ports I6 spaced inwardly of the piston. Y The piston rod is provided at a point contiguous with the piston II with an enlarged cylindrical portion IIa of smaller diameter than the piston. 'This enlargement defines a stop shoulder IIb the large annular face of which adapts it to abut'the gland I4 in a non-injurious manner to limit the stroke of the piston in one direction. VThe portion IIa is circumferentially spaced from the pump barrel thereby permitting free flow of fluid through the ports I6, which, it is noted, extend through the portion I Ia.

The piston II is formed with a circumferentially extending groove Il to receive a packing` der 24 and being held in place by means of a snap ring 25 mounted in a groove 26 and engaging the outer end of the seat member. A. sealing ring 2l of circular cross section is mounted in a groove It should be noted that the piston-carried valve unit may be readily assembled through the outer end of the piston, the parts being placed in the bore i5 in the order shown in Fig. 3.v Likewise the valve parts are subject to easy replacement through the piston ii upon removing the snap rmg.- a

It is important to note that screw threaded joints such vas .heretofore employed between the piston and the piston rod, or for holding the seat -member or other parts in place, are eliminated thereby eliminating alignment errors heretofore I encountered.

The particular construction of the piston simplies machining operations and reduces the cost of the unit as well as the number of separate' parts compared to pistons heretofore used in this art. Inasmuch as the pump with which my improved piston is used is employed for emergency purposes in aircraft, it is apparent it is of vital importance that the pump be ready at all times for dependable and accurate performance. This is assured by reasonv of the particular piston construction of the present invention, the elimination of separate piston and piston rod units, and all screw threaded joints.

` The pump hereof operates in the manner well known in the art, the stroke of the piston in a direction away from valved inlet port 8 drawing in iiuid While at the same time pumping through the outlet port 9 the fluid trapped between the piston il and the gland i4. The check valve 22 is closed by the pressure of iiuid developed as the piston is moved in the direction above noted.

When the piston is moved towards the valved inlet port 8, the check valve 8a associated-with said port is closed by the pressure of the fluid against it, while the check valve 22 opens and some of the fluid is forced through bore i5, ports I6 into the portion of the barrel surrounding the piston rod I0, thence out through port 9.

While I have shown and described a specific embodiment of my invention I do not'limit myself to the exact details of construction set forth, and the invention embraces such changes, modifications and equivalents of the parts and their formation and arrangement as come within the purview of the appended claims.

, I claim:

.1. In a piston assembly, a piston rod.- a piston formed integral with one end of said rod and having an axial bore extending therethrough and I into said rod, said rod having a port therein opening into said bore, a cylindrical valve seat member in said bore between the outer end of in said bore to hold said valve seated, and a snap ring mounted in said bore and holding the seat member, valve and spring in place.

, 2. Ina piston assembly, a piston rod, a piston formed integral with one end of said rod and having an axial bore extending therethrough and 'into said rod, said rod having a port therein opening into said bore, a cylindrical valve seat member in said bore between the outer end of the bore and said port insertable and removable through said outer end of the bore, a checl: valve mounted in said bore so as to seat against the inner end of said seat member, a spring mounted in said bore to hold said valve seated, and a snap ring mounted in said bore and holding the seat member, valve and spring in place, said piston having an annular shoulder in said bore against which the inner end of said seat member is engaged, said snap ring contacting the outer end of said seat member. i i

3. In a piston assembly, a piston rod, a piston formed integral with one end of said rod and having an axial bore extending therethrough and into said rod, said rod having a port therein opening into said bore, a cylindrical valve seat m'ember in said bore between the outer end of the bore and said port insertable and removable through said outer end of the bore, a check valve mounted in said bore so as to seat against the inner end of said seat member, a spring mounted in said bore to hold said valve seated, and a snap ring mounted in said bore and holding the seat member, valve and spring in place, said rod havinga shoulder in said bore, said piston having a shoulder in said bore, a stop member in the bore seated on the shoulder 'on the rod and engaging the inner end of said spring, said seai member having its inner end engaged with the shoulder on the piston.

4. In a piston'assembly, a piston rod, a piston formed integral with said rod at one end thereof and having a bore extending therethrough from the outer end thereof and into said rod, said rod having an enlarged cylindrical portion between it and said piston, said enlarged portion being of smaller diameter than the piston and having radialports opening into said bore and on the periphery of said enlarged portion, a tubular valve seat member mounted in said bore between said ports and the outer end of the bore, a springloaded check valve adapted to seat against said seat member, and means removably mounted in said bore for holding said seat member in place.

5. In a piston assembly, a piston rod, a piston formed integral with said rod at one end thereof and having a bore extending therethrough from t-he outer end thereof and into said. rod, said rod having an enlarged cylindrical portion between it and said piston, said enlarged portion being of smaller diameter than the piston and-having radial ports opening into said bore and on the periphery of said enlarged portion, a tubular valve said bore for holding said seat member in place,

lthe bore and said port insertable and removable Y through said outer end of the bore, a check valve mounted in said bore so as to seat against the innerjend of said seat member, a spring mounted said enlarged cylindrical portion defining a stop shoulderadapted to limit the movement ofthe enlarged portion being of smaller diameter than the piston and having radial ports opening into asid bore and on the periphery of said enlarged portion, a tubular valve seat member mounted in said bore between said ports and the outer end of the bore, a spring-loaded check valve adapted ing with one end potion of said piston chamber,

an annular packing gland fitted within the oppositeend portion of said piston chamber; a piston assembly including a' piston rod having a working t within saictannular packing gland, a piston formed integral with said rod at one end thereof and having a bore extending therethrough from the outer'end thereof and into said rod, said rod having an enlarged cylindrical portion between it and said piston which forms an annular stop shoulder abuttable against said gland, said enlarged portion being of smaller diameter than the piston and having radial ports opening into said bore and on the periphery of said enlarged por- ,tion, a tubular valve seat member mounted in said bore between said ports and the outer end of the bore, and a spring loaded check valve mounted within said bore to seat against said valve seat member.

8. In a piston assembly, a piston rod, a piston carried by one end of said rod, there being an axial bore through said piston and extending into said rod, an annular Valve seat removably mounted Within the portion of said bore contained within said piston, a check valve Within said bore to seat against said valve seat, said bore having an annular shoulder around it in its mid-length portion, a disk insertable into said bore through the portion thereof which passes through said piston and seated upon said annular shoulder, and a spiral compression spring one end of which abuts against said diskand the opposite end of which engages said cheek valve to seat the latter,

said piston rod having-'ports through its wall between said valve seat and disk.

9. In a piston assembly, a piston rod, a piston carried by one end of said rod, there being an axial bore through said piston' and extending into said rod, an annular valve seat removably mounted within the portion of said bore con,- tained within said piston, a check valve within said bore to seat against said valve seat, said bore having an annular shoulder around it within the mid-length portion of said rod, a disk insertable into said bore through the portion thereof Which passes through said piston and seated upon said annular shoulder, and a spiral compression spring one end of which abuts against said'disk and the opposite end of which engages said check valve to seat the latter, said piston rod having ports through its wall between said valve seat and disk, said bore continuing into said piston rod from said annular shoulder to a point adjacent to theend thereof which is opposite to the aforesaid piston, and means carried by the latter end of said rod for attaching an operating means thereto.

10. In a piston assembly, a piston rod, a piston carried by one end of said rod, there being an axial bore through said piston and extending into said rod, an annular valve sea't removably mounted within thev portion of said bore contained within said piston, a check vvalve withinsald bore to seat against said valve seat, said bore having an annular shoulder around it in its mid-length portion, the material which forms said shoulder being integral with the surrounding portion of said piston rod, and a spiral spring one end of which engages said check valve to seat the latter, the opposite end of said spring being opposed by said annular shoulder, said piston rod having ports through its wall lbetween said valve sea and annular shoulder. i

JOHN WILLIAM KELLY. 

